In loading dock operations, particularly where motorized fork-lift vehicles are utilized, safety is of paramount concern for the protection of personnel, equipment, and goods being handled. In many instances, human error is the principal cause resulting in severe personnel injury and/or serious damage to goods and equipment. In many loading dock facilities, loading stations are provided which utilize vertically adjustable platforms or dock lifts which may be lowered within a pit or recess formed in the exposed horizontal surface of the loading dock. In such installations when the dock lift is in its fully lowered position, the truck to be loaded or unloaded may be spotted on the dock lift and then the latter raised to the desired height or a fork-lift vehicle may be spotted on the dock lift and raised or lowered, as required, to effect loading or unloading of a parked truck.
In addition to or in lieu of the vertically adjustable platform or dock lift, a dock-leveler may be provided which is hingedly adjustable to compensate for any height differential which might exist between the exposed horizontal surface of the loading dock and the bed of the truck parked at the dock station during loading or unloading thereof.
When the dock lift and/or the dock leveler are in their normal rest position, that is to say when the exposed horizontal surface thereof is in coplanar relation with the adjacent horizontal dock surface, there is an ever-present danger of the fork-lift vehicles and the like when carelessly maneuvered across the coplanar surface, falling off the edge of dock with extremely serious life-threatening consequences. In situations where the platform or dock lift is lowered relative to the horizontal dock surface careless maneuvering of the fork-lift vehicles can cause them to fall onto the recessed dock lift or drive off an exposed edge of loading dock.
In many loading dock facilities, access passageways to the interior of a warehouse, plant or like building are aligned with the various loading/unloading stations provided along the dock facility. Each such passageway is normally provided with a security door which may be in a closed or open position when the station is not being used. When in the closed position, such a security door is susceptible to being hit or struck on the inside by a load-handling vehicle being maneuvered within the warehouse, plant or like building. When, however, the security door is raised for ventilating purposes, there is a danger that a fork-lift vehicle or the like might accidentally pass through the open passageway and fall off the dock platform.
Heretofore, in attempting to remedy these hazardous situations, complex and expensive structures have been installed at the various stations which require an inordinate amount of space and are highly susceptible to malfunction. Furthermore, such structures in some instances require special power sources which added materially to the initial product costs. Lastly, such prior structures are incapable of withstanding heavy impact forces from loaded fork-lift vehicles and the like which may occur during normal fork-lift traffic.